ide: add ide_queue_pc_head() helper

* Move REQ_IDETAPE_* enums to <linux/ide.h>.

* Add ide_queue_pc_head() and convert ide-{floppy,tape}.c to use it
  instead of ide*_queue_pc_head().

* Remove no longer used ide*_queue_pc_head().

There should be no functional changes caused by this patch.

Acked-by: Borislav Petkov <petkovbb@gmail.com>
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

include/linux/ide.h

@@ -1121,6 +1121,22 @@ int ide_check_atapi_device(ide_drive_t *, const char *);
 
 void ide_init_pc(struct ide_atapi_pc *);
 
+/*
+ * Special requests for ide-tape block device strategy routine.
+ *
+ * In order to service a character device command, we add special requests to
+ * the tail of our block device request queue and wait for their completion.
+ */
+enum {
+	REQ_IDETAPE_PC1		= (1 << 0), /* packet command (first stage) */
+	REQ_IDETAPE_PC2		= (1 << 1), /* packet command (second stage) */
+	REQ_IDETAPE_READ	= (1 << 2),
+	REQ_IDETAPE_WRITE	= (1 << 3),
+};
+
+void ide_queue_pc_head(ide_drive_t *, struct gendisk *, struct ide_atapi_pc *,
+		       struct request *);
+
 ide_startstop_t ide_pc_intr(ide_drive_t *drive, struct ide_atapi_pc *pc,
 	ide_handler_t *handler, unsigned int timeout, ide_expiry_t *expiry,
 	void (*update_buffers)(ide_drive_t *, struct ide_atapi_pc *),